title: Evidence for the strong effect of quenched correlated disorder on phase separation and magnetism in (La(1-y)Pr(y))0.7Ca0.3MnO3.
abstract: High resolution neutron diffraction shows that the mesoscopic separation into ferromagnetic (FM) and antiferromagnetic (AFM) phases and the FM transition temperature T(C) in the perovskite manganite (La(1-y)Pr(y))(0.7)Ca(0.3)MnO(3) strongly depend on the quenched correlated disorder. The different disorder strengths are achieved by different procedures of the sample synthesis and are quantitatively characterized by the microstrain-type diffraction peak broadening. The system shifts to predominantly a one-phase state with smaller T(C) as the correlated disorder strength is decreased, supporting the viewpoint that the origin of phase separation in the indicated manganite system is the correlated quenched disorder. The ground state of an ultimately chemically homogeneous sample is FM-like containing about 20% of the AFM minority phase. This FM-like state can be readily transformed to the AFM-like one having < 20% of the FM phase by the decrease of the effective charge carrier bandwidth via oxygen isotope substitution.
authors.affiliation: Laboratory for Neutron Scattering, ETH Zurich and Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland. Vladimir.Pomjakushin@psi.ch
authors.forename: V Yu
authors.initials: VY
authors.lastname: Pomjakushin
authors.forename: D V
authors.initials: DV
authors.lastname: Sheptyakov
authors.forename: E V
authors.initials: EV
authors.lastname: Pomjakushina
authors.forename: K
authors.initials: K
authors.lastname: Conder
authors.forename: A M
authors.initials: AM
authors.lastname: Balagurov